This invention relates to a spinning machine having several spinning stations for the spinning of yarns from slivers which are fed to the spinning stations in cans, guiding devices for the slivers being provided between the cans and the spinning stations.
The feeding of the fiber material to be spun in the form of slivers disposed in cans is known, for example, in the case of open-end spinning machines. In the case of the machines which are available on the market, the slivers are withdrawn directly by the sliver feeding device of the individual spinning stations from the cans disposed in front of and partly below the spinning arrangement.
It is also known (German Patent Document DE-C 23 35 740), in the case of open-end spinning machines, to arrange the cans on a platform above the spinning machine and feed the slivers through guiding tubes to the spinning stations. These guiding tubes, which are provided with baffles, are to serve as an intermediate storage device which, on the basis of a special construction, is fed by a continuously running feeding device nevertheless intermittently. Then the sliver is to be guided through the respective guiding tube essentially without tensile stress.
The feeding of the fiber material in the form of slivers made available in cans is also known in the case of other fast-running spinning machines, such as wind-around spinning machines or air spinning machines. As a rule, these are one-sided machines, in the case of which the slivers withdrawn from the cans deposited on the rear side of the spinning machine are fed to the spinning stations from above. In this case, guiding devices for the slivers are provided in the form of pulleys and guide rods.
It is also known (German Patent Document DE-PS 817 572) to feed slivers in cans in the case of ring spinning machines, in which case the cans are deposited on platforms or in a space above the spinning machine. In this case, relatively long travelling paths are obtained with one or several vertical sections which lead to the risk that the slivers may hang out; that is, are drafted uncontrollably as a result of their own weight. Such an arrangement is therefore possible only for slivers which have a relatively coarse size and thus a relatively high strength.
However, the spinning of slivers of coarse sizes is very difficult on ring spinning machines. Since the ring spinning machines have only a relatively low delivery speed at the outlet of the drafting units, the feeding rollers of the drafting units--while the required drafting is taken into account--must run very slowly; that is, at rotational speeds of one revolution per minute and less. It is technically extremely difficult to let long shafts, like the feeding rollers of drafting units, run at such low rotational speeds with sufficient precision. There is the risk that these shafts will rotate only jerkily so that no controlled draft is obtained. The feeding of the fiber material to be spun in cans has therefore not been carried out successfully in practice in the case of ring spinning machines.
In an older German Patent Application (P 40 41 112.5, PA 1170, P 9342), which is no prior publication, it is suggested to provide guiding devices which comprise drivable guide pulleys which are arranged to be offset with respect to one another in a vertical section so that the slivers are guided in a slalom-type manner from pulley to pulley. In the same older patent application, a further variant is suggested in which the slivers are guided on their path to the drafting units between two guiding aprons disposed against one another.
It is an object of the invention to develop a spinning machine of the initially mentioned type in such a manner that fine slivers may also be fed in cans without the risk of faulty drafts, particularly in vertical sections of the transport path.
This object is achieved according to preferred embodiments of the invention in that the guiding devices comprise several clamping devices which are arranged behind one another and transport the respective sliver.
In the case of the development according to the invention, it is achieved that the slivers are supported and are nevertheless moved in the transport direction. As a result, it is possible to feed also relatively thin slivers in cans; that is, slivers of sizes of approximately Nm 0.4 to 0.8. In this case, these fine slivers may also be transported in the vertical direction along larger sections. It is therefore possible to carry out a can feeding also in the case of ring spinning machines because, on the basis of the slivers with the fine sizes, while taking into account the draft, the feeding roller pairs of the drafting units still run at a sufficiently high speed so that a uniform round rotating is ensured. By means of this can feeding, it will then be possible, in the case of ring spinning machines, to do without a premounted machine, specifically the flyer. In the case of other spinning machines, which are equipped with drafting units into which the slivers travel, it is possible to feed finer slivers so that then the drafting units may be simplified. For example, in the case of machines of this type, there is the possibility to use, instead of five-cylinder drafting units, the three-cylinder drafting units which are customary today in the case of ring spinning machines.
Also in the case of open-end machines, the feeding of finer slivers results in advantages because then the opening-up work for the separating of the fibers is reduced so that, during the opening-up, the fibers are processed more carefully. It is therefore possible to spin finer yarns with less damaged fibers so that the yarns have a higher quality.
In an advantageous development of the invention, the clamping devices are formed by drivable roller pairs. By means of this arrangement, longer paths with many curves can also be bridged, in which case the expenditures are relatively low.
In another development of the invention, the clamping devices may be formed by clamping jaws which are arranged on guiding belts, of which two are assigned to one sliver. In this case, the clamping devices are held so that they are movable in the transport direction of the sliver so that an existing clamping is maintained along the whole transport path.
In the case of the addressed clamping, the sliver must only be pressed slightly; that is, the clamping devices must contact one another only slightly or possibly not at all. The slight clamping can be achieved in that the clamping devices are slightly recessed in the area of the sliver.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.